Method of making hydrogen chlorid and sodium sulfate.



UNITED STATES PATENT OFFICE.

THEODOR MEYER, OF BUERGEIJ, GERMANY, ASSIGN OR TO FIRM OF K.

OEHLER, ANILIN- dz; ANILINFARBEN- FABRIK, OF OFFENBAOH-ON- THE MAIN,GERMANY.

METHOD OF MAKING HYDROGEN CHLORID AND SODIUM SULFATE.

SPECIFICATION forming part of Letters Patent No. 702,877, dated June 17,1902.

Application filed February 12, 1902. Serial No. 93,778. (No specimens.)

T0 to whont it may concern:

Be it known thatI, THEODOR MEYER, doc tor of philosophy, chemist,residing at Offenbacherstrasse 114, Buergel, near Offenbachon-the-/Iain, Germany, have invented new and useful Improvements in theManufacture of Sodium Sulfate and Hydrogen Ohlorid, of which thefollowing is a specification.

This invention relates to the manufacture of hydrogen chlorid and sodiumsulfate (Glauber salt) by heating together common salt and sodiumbisulfate. In such manufacture as heretofore practiced the materialshave been simply crushed, and in that state they have been heatedtogether to very high temperatures, commonly to a good red heat andsometimes to the fusing-point, in a furnace in which they weremechanically agitated or were stirred by hand through an open door.

The present improvement is based upon the discovery which I have madethat when an intimate mixture of chemically-proper proportions-that isto say,equimolecular proportions-of common salt and bisulfate, both mostfinely powdered, is heated in a closed retort to about 400 centigradeonly the hydrogen chlorid is completely developed in the short time ofabout forty minutes after the charging of the vesselwithout anystirringand the sulfate obtained is of a faultless (chemical and physical) primequality. In carrying out my invention I grind the salts so fine as topass a sieve of four hundred meshes to the square centimeter and insteadof a reverberatory furnace or a large fire brick muffle, in which thesalt masses are moved and stirred by hand or mechanically at atemperature of 800 to 900 centigrade and Where but diluted gases areobtained, I use a simple small retort closed air-tight, containing fromtwo hundred to three hundred kilograms of the mixture at a temperatureof about 400 centigrade only, and I get a pure gas of nearly one hundredper cent. real HOl.

In my process a partial fluxing does not take place, for any particle ofbisulfate being about to flux will immediately be converted into neutralsulfate by a neighboring particle of common salt. Thus the mass does notadhere to the sides of the retort, but slags to a crumbly sulfate ofbest quality. The temperature being very moderate and regular, theevolved hydrogen chlorid is also nearly free from sulfuric acid and maybe easily and completely condensed by water to a hydro chloric acid ofhighest concentration, as long as care is taken to keep down thetemperature. By proper management of the apparatus in this proceeding anescaping of hydrochloric-acid vapors is quite out of question. Thoughnot necessary, it is, however, advis able to move the acid gases forwardby slight suction through a fan-blast attached at the end of acondenser. The hydrogen chlorid does not contain any impurities except asmall percentage of water, and may instead of being transformed intohydrochloric acid by water absorption be condensed by pressure andcooling to a liquid state after having been dried by concentratedsulfuric acid or the like.

I do not limit myself to the quantity of two hundred to three hundredkilograms nor to the temperature of 400 centigrade. If I go down to,say, 350 centigrade, the reaction will take place; but a far longer timewill be necessary to complete the conversion. If I raise the temperatureover 400 centigrade, the reaction will be completed in a shorter timethan forty minutes; but care must be taken that the temperature shouldnot be al lowed to rise to the melting-point.

What I claim as my invention is- 1. The within-described improvement inthe process of manufacturing concentrated hydrogen chlorid and sodiumsulfate which consists in finely powdering and intimately mixing inabout equimolecular proportions common salt and sodium bisulfate andheating the same to a temperature below the melting-point.

2. The within-described improvement in the process of manufacturinghydrogen chlorid and sodium sulfate which consists in finely powderingand intimately mixing in about equimolecular proportions common salt andsodium bisulfate and heating the mixture in a closed vessel to atemperature of about 400 centigrade.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

TI-IEODOR MEYER.

Witnesses:

HERMANN Wns'r, ROBERT B'UHL.

